Re: Dinosaurian Class (was: DROMAEOSAURS AND OVIRAPTOROSAURS ....)

[Jack <jconrad@lib.drury.edu>]

On Wed, 17 Jun 1998, Bryan R. Stahl wrote:

> Does this mean we're all bacteria?<g>
> 
> Bryan


No, but we are eukaryotes!  I am a deplorable fence straddler, but I don't
feel that Linnaean systematics can stand alone.  I feel that cladistics is
great for those who are really into systematics (like myself), but in
dealing with people who are not as interested and who are not as informed
(not to say that I'm informed by any means, I fall under interested) we
NEED grades.  People I've encountered generally know that reptiles have
their own class.  Now, by applying cladistics to Linnaean systematics
(cringe of everyone on the list) we can make a system that might be handy
for the neophyte and has something to do with reality for the experts.  An
example would be Archosauriformes.  Okay so we have reptiles and the
characteristics the layman will immediately associate with reptiles are
scaley skin, 3 chambered heart, and (usually) sprawling gait.
Archosauriformes had scaley skin, but some members had feathers.  The
heart was probably 4 chambered (or very nearly, see crocodylians and
birds).  The gait was, for the most part, improved to erect.  This seems
like a sensible place to invent a "class" for the lay public.  

Of course I don't expect any of this to really take off, but as a concept
I feel it could work (then again, communism is a wonderful concept that
hasn't worked well in practice).  Would this make reptiles paraphyletic?
Yes and here is a big subject not lightly delved into.  What non-reptilian
sauropsids are there?  As far as I can tell, only mesosaurs (see T. Mike
Keesey's wonderful site which has all the latest in systematics at
<http://www.gl.umbc.edu/~tkeese1/dinosaur>) If mesosaurs are the only
non-reptilian sauropsids, would it not be better to simply drop Reptilia
and its commonly associated characteristics (not always appropriately
associated characteristics at that) in favor of Sauropsida in cladistic
use?  Then we could still have our paraphyletic Class: Reptilia, Class:
Pelycosauria, Class: Neosynapsida (incl. mammals) and Class: Archosauria
(or Archosauriformes if you prefer) while maintaining no descrepincy with
cladistics.  

As before, I'm sure that this cannot be accepted by most of you
(particularly T. Mike Keesey whose opinion I highly respect though cannot
always agree with), and I will admit that there are definite problems with
this system.  It does, however, seem more wieldly for the non-expert than
cladistics, but still takes advantage of part of cladistics.  

Any input is welcome.  I may like to stir things up every once in a while
with somewhat half-cocked ideas (see my post yesterday), but it helps
stimulate my thoughts to receive the opinions of others and I gratefully
accept any criticism.  

Jack Conrad
<jconrad@lib.drury.edu)